Added data and protocols description for Multipie

doc/leaderboard/multipie.rst

 .. vim: set fileencoding=utf-8 :
 
-.. _bob.bio.face.learderboard.multipie:
+.. _bob.bio.face.leaderboard.multipie:
 
 ================
 Multipie Dataset
 ================
 
-
 .. todo::
    Benchmarks on Multipie Database
 
-   Probably for Manuel's students
+   Probably for Manuel's students
\ No newline at end of file
+
+Database
+========
+The `CMU Multi-PIE face database <http://www.cs.cmu.edu/afs/cs/project/PIE/MultiPie/Multi-Pie/Home.html>`_ contains more than 750,000 images 
+of 337 people recorded in up to four sessions over the span of five months. Subjects were imaged under 15 view points and 19 illumination 
+conditions while displaying a range of facial expressions. In addition, high resolution frontal images were acquired as well. 
+In total, the database contains more than 305 GB of face data. 
+
+Content
+*******
+The data has been recorded over 4 sessions. For each session, the subjects were asked to display a few
+different expressions. For each of those expressions, a complete set of 30 pictures is captured that includes
+15 different view points times 20 different illumination conditions (18 with various flashes, plus 2 pictures with no flash at all). 
+
+Available expressions
+---------------------
+* Session 1 : *neutral*, *smile*
+* Session 2 : *neutral*, *surprise*, *squint*
+* Session 3 : *neutral*, *smile*, *disgust*
+* Session 4 : *neutral*, *neutral*, *scream*.
+
+Camera and flash positioning
+----------------------------
+The different view points are obtained by a set of 13 cameras located at head height, spaced at 15° intervals,
+from the -90° to the 90° angle, plus 2 additional cameras located above the subject to simulate a typical
+surveillance view. A flash coincides with each camera, and 3 additional flashes are positioned above the subject, for a total
+of 18 different possible flashes.
+
+The following picture showcase the positioning of the cameras (in yellow) and of the flashes (in white).
+
+.. image:: img/multipie_setup.jpg
+    :width: 620px
+    :align: center
+    :height: 200px
+    :alt: Multipie setup
+
+File paths
+----------
+
+The data directory structure and filenames adopt the following structure:
+ 
+.. code-block:: shell
+   
+   session<XX>/multiview/<subject_id>/<recording_id>/<camera_id>/<subject_id>_<session_id>_<recording_id>_<camera_id>_<shot_id>.png
+
+For example, the file
+
+.. code-block:: shell
+   
+   session02/multiview/001/02/05_1/001_02_02_051_07.png
+
+corresponds to
+* Subject 001
+* Session 2
+* Second recording -> Expression is *surprise*
+* Camera 05_1 -> Frontal view
+* Shot 07 -> Illumination through the frontal flash
+
+Protocols
+*********
+
+Expression protocol
+-------------------
+**Protocol E**
+
+* Only frontal view (camera 05_1); only no-flash (shot 0)
+* Enrolled : 1x neutral expression (session 1; recording 1)
+* Probes : 4x neutral expression + other expressions (session 2, 3, 4; all recordings)
+
+Pose protocol
+-------------
+**Protocol P**
+
+* Only neutral expression (recording 1 from each session, + recording 2 from session 4); only no-flash (shot 0)
+* Enrolled : 1x frontal view (session 1; camera 05_1)
+* Probes : all views from cameras at head height (i.e excluding 08_1 and 19_1), including camera 05_1 from session 2,3,4.
+
+Illumination protocols
+----------------------
+N.B : shot 19 is never used in those protocols as it is redundant with shot 0 (both are no-flash).
+
+**Protocol M**
+
+* Only frontal view (camera 05_1); only neutral expression (recording 1 from each session, + recording 2 from session 4)
+* Enrolled : no-flash (session 1; shot 0)
+* Probes : no-flash (session 2, 3, 4; shot 0)
+
+**Protocol U**
+
+* Only frontal view (camera 05_1); only neutral expression (recording 1 from each session, + recording 2 from session 4)
+* Enrolled : no-flash (session 1; shot 0)
+* Probes : all shots from session 2, 3, 4, including shot 0.
+
+**Protocol G**
+
+* Only frontal view (camera 05_1); only neutral expression (recording 1 from each session, + recording 2 from session 4)
+* Enrolled : all shots (session 1; all shots)
+* Probes : all shots from session 2, 3, 4.
+
+
+
+Benchmarks
+==========
+
+Run the baselines
+*****************
+
+Leaderboard
+***********
+